Osmosis pre-treatment process helps to reduce partially the moisture of fruits and vegetables before drying. The application of low pressure during the first few minutes of osmosis pushes the trapped gases out and facilitates the penetration of hypertonic solution into the food, thereby improving mass transmission efficiency. In this work, the effects of sucrose concentration (52–68o Brix), vacuum level (516–684 mmHg), and its application time (5–15 min) on water loss (WL) and solid gain (SG) of black cherry tomatoes (cv. OG) were investigated. The response surface methodology with a factorial experimental central composite design was used for the optimization. Results indicated that the application of a vacuum level of 627.22 mmHg every first 11.61 min of 1 h osmosis in a sucrose solution of 59.38o Brix increased the WL and reduced the osmosis time. The maximum WL was 28.60% of the tomatoes weight after 4 h of osmosis and the SG was 2.94%. Meanwhile, the corresponding values for the control sample (without vacuum application) were 15.62% and 1.66% after 5.5 h of osmosis dehydration. This proves the effectiveness and potential of the vacuum application in the osmotic dehydration process of black cherry tomatoes.
Key words: bioactive compound, black cherry tomato, osmotic dehydration, solid gain, vacuum application, water loss
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